A method for the determination of pyruvate carboxylase activity during the glutamic acid fermentation with Corynebacterium glutamicum

A discontinuous lactate dehydrogenase coupled assay is described for the evaluation of the pyruvate carboxylase activity (Pc, EC 6.4.1.1) in a glutamate overproducing strain of Corynebacterium glutamicum. After an initial permeabilisation period of the cells, the method consisted of the fluorometric determination of the remaining pyruvate level after transformation into oxaloacetate by the endogenous Pc. The assay was demonstrated to be powerful and enabled the determination of the C. glutamicum Pc activity grown on different carbon sources. Besides, this method was used to assay Pc activity in C. glutamicum 2262 during a temperature triggered glutamate producing process with biotin excess or limitation.